Various types of scaffolding are known in the prior art. Large scaffolding which can extend up, for example, a number of floors of a building which is being constructed of repaired is one type that is employed. Such scaffolding is, typically, anchored in some manner to the building or structure which is being ascended. Anchoring of this nature is necessary because of the weight of the scaffolding segments and the catastrophic results that would be occasioned should the scaffold fall.
Obviously, scaffolding of this nature has drawbacks. While it enables workers to perform tasks and functions at significant heights, once it is in place, it becomes substantially immobile. If the scaffolding needs to be transferred to a different location--even one closing proximate its original location--significant time must be invested in accomplishing the transfer.
In view of these drawbacks, lighter and more mobile scaffolding is employed wherever possible. If a job involves, for example, painting at a height of approximately six to ten feet, a lighter more portable type of scaffolding can be utilized. This type of scaffold typically includes a pair of end frames which are maintained in position opposite one another by a plank-like member having a working surface, which member is disposed generally horizontally to interconnect the end frames. Typically, such a working surface can be disposed at a plurality of heights so that the maximum height which can be reached by a worker standing thereon can be varied.
Each end framed is frequently constructed in the form of a ladder. That is, it includes two uprights interconnected by a plurality of rungs. When the scaffolding is assembled with the working surface member interconnecting the end frames, the uprights of the end frames are disposed generally vertically and the rungs are spaced vertically from one another, typically at equal distances.
Frequently, the lower end of each of the four uprights is provided with a caster. A structure so constituted is mobile, and, once it is finished being used in a particular location, it can quickly and easily be moved to another location.
Because of applications to which scaffolding of this type is put, it typically involves being moved frequently. For example, when the scaffolding is being used to paint a high ceiling, once the painter completes a segment accessible with the scaffolding in a particular location, the scaffolding must be moved to another location generally adjacent that it previously occupied. Depending upon the size of the room, the scaffolding might be moved numerous times before the ceiling's painting is completed.
As can be seen, scaffolding of this lighter more mobile type has significant advantages over that for employment for larger projects, as previously described. There are, however, trade-offs. For example, because of its lighter weight and greater mobility, it tends to be less stable. This drawback is further aggravated by circumstances in view of the construction typically provided to the end frames. Because of their ladder-like appearance, workers utilizing the scaffold are encouraged to mount the scaffolding by climbing up the rungs of one or the other of the end frames.
Workers can minimize the hazards involved by climbing to the top of the end frame and down the other side (that is, the inside of the scaffolding) to climb onto the working surface. This becomes relatively inconvenient, however, when the working surface is only at a relatively small percentage of the distance up the end frames.
In order to save time and effort, workers typically climb to the height at which the working surface is positioned and swing outwardly around the end frame being climbed in order to get onto the working surface. When this occurs, depending upon the weight of the material of which the scaffolding is made, the center of gravity can be transferred outside the base of the scaffold. When this occurs, the scaffolding will tip over.
Certainly, the scaffolding could be made safer by making the end frames and the plank-like member defining the working surface of very heavy materials. By taking such action, however, the advantages of lighter weight and greater mobility normally inherent in a smaller scaffold of this type are negated.
The present invention is improved means for ascending a light-weight mobile scaffold of this type. It is directed to solving the problems of the prior art and providing desirable characteristics without negating the advantages of such scaffolding.